Method of dispersing metal oxides and hydroxides in lubricating oils



Patented Apr. 27, 1954 UNITED STATES PATENT OFFICE METHOD OF DISPERSING METAL OXIDES AND HYDROXIDES IN LUBRICATING OILS No Drawing. Application December 30, 1950, Serial No. 203,7 83

6 Claims. 1

This invention pertains to a method of dispersing polyvalent metal oxides and hydroxides in lubricating oils.

During normal operation of internal combustion engines, acids are formed in the lubricating oil itself and in the combustion chamber. The acids formed in the lubricating oil itself are normally caused by oxidation of the lubricating oil during engine operation. The resulting organic acids and peroxides break down the lubricating oil and contribute to wear by corrosion. The combustion chamber acids normally come from the combustion products of the fuel. For example, when high sulfur fuels are used in diesel engines, sulfuric acid is formed from the sulfur. This sulfuric acid finds its way into the crankcase along with the blow-by gases.

Large amounts of detergents are being incorporated in lubricating oil compositions for use as dispersing agents and, incidentally, as neutralizing agents for these acids. For example, calcium oetyl phenate is incorporated into a lubricating oil composition primarily to serve as a detergent. However, a portion of the calcium cetyl phenate reacts with the sulfuric acid formed from high sulfur fuels to form calcium sulfate, neutralizing the effect of the acids, and removing a part of the detergent from its intended purpose.

Rather than use relatively expensive organic compounds to neutralize the acids formed during the operation of an engine, it would be more practical to use relatively inexpensive inorganic materials for this purpose. Likewise, it is more practical to use a detergent in a lubricating oil composition primarily for its intended purpose, not for the purpose of neutralizing acids. Furthermore, the inorganic materials which can be used to neutralize acids in lubricating oils will neutralize larger amounts of acids per unit weight than the organic compounds.

It is a primary object of this invention to provide a method for dispersing polyvalent metal oxides and hydroxides in lubricating oil.

It is therefore an object of this invention to rovide lubricating oil compositions containing stable dispersions of relatively inexpensive inorganic acid-neutralizing compounds.

It is also an object of this invention to form clear, filterable dispersions of polyvalent metal oxides and hydroxides in lubricating oil cornpositions.

It is another object of this invention to form colloidal dispersions of polyvalent metal oxides and hydroxides in lubricating oil.

It is a still further object of this invention to provide means for colloidally dispersing relatively oil-insoluble polyvalent metal oxides and hydroxides in lubricating oil.

These and other objects of this invention will be apparent from the ensuing description and the appended claims.

It has been discovered that col1oida1 dispersions (colloidal solutions) of polyvaient metal oxides and hydroxides in lubricating oils can be obtained by the use of dihydric alcohols; the dispersions stabilized by dispersants.

According to the present invention, polyvalent metal oxides and hydroxides are dispersed in lubricating oils by a method involving the use of dihydric alcohols, which dispersion is stabilized by a dispersant. The polyvalent metal oxides and hydroxides normally are dissolved (or dispersed) in a dihydric alcohol. The dihydric alcohol solutions (or dispersions) are then thoroughly blended with lubricating oils to form dispersions of polyvalent metal oxides or hydroxides, which dispersions are stabilized by dispersants.

Lubricating oils in which the polyvalent metal oxides and hydroxides can be dispersed according to the present invention include a wide variety of lubricating oils such as naphthenic base, parafiin base, and mixed base mineral oils, other hydrocarbon lubricants, e. g., lubricating oils derived from coal products and synthetic oils, e. g., alkylene polymers (such as polymers of propylene, butylene, etc., and mixtures thereof), alkylene oxide type polymers, dicarboxylic acid esters and liquid esters of acids of phosphorus. Synthetic oils of the alkylene oxide type polymer which may be used include those exemplified by alkylene oxide polymers (e. g., propylene oxide polymers) and derivatives, including alkylene oxide polymers prepared by polymerizing alkylene oxides (e. g., propylene oxide) in the presence of Water or alcohols, e. g., ethyl alcohol, and esters of alkylene oxide type polymers, e. g., acetylated propylene oxide polymers prepared by acetylating the propylene oxide polymers containing hydroxyl groups.

Synthetic oils of the dicarboxylic acid ester type include those which are prepared by esterifying such dicarboxylic acids as adipic acid, azelaic acid, suberic acid, sebacic acid, alkenyl succinic acid, fumaric acid, maleic acid, etc., with alcohols such as butyl alcohol, hexyl alcohol, Z-ethylhexyl alcohol, dodecyl alcohol, etc. Examples of dicarboxylic acid ester synthetic oils include dibutyl adipate, i r t ethylhexyl sebacate, di-n-hexyl fumarate polymer, etc.

Synthetic oils of the type of liquid esters of acids of phosphorus include the esters of phosphoric acid, e. g., tricresyl phosphate; the esters of phosphonic acid, e. g., diethyl ester of decane phosphonic acid, or other such esters as obtained by reacting alkyl phosphonyl chlorides with hydroxyl-containing compounds, such as phenols and aliphatic alcohols, and with olefin oxides such as propylene oxide, as described in Jensen et a1. U. S. application No. 86,856, filed April 11, 1949, now abandoned.

The polyvalent metal oxides and hydroxides which are dispersed in lubricating oil compositions according to this invention include the oxides and hydroxides of the metals of Groups II, III, IV and VIII of Mendeleefs Periodic Table of Elements, particularly calcium, magnesium, strontium, barium, lead, tin, zinc, cadmium, iron, cobalt, nickel and aluminum.

The dihydric alcohols used to disperse the polyvalent metal oxides and hydroxides in lubricating oils according to the present invention are dihydric alcohols containing up to 6 carbon atoms. Suitable dihydric alcohols include, for example, ethylene glycol, propylene glycol, butane diol-2,3; pentane dim-2,4; Z-methyl butane diol-1,3; 2-methyl butane-2,4 and 2-methyl butane diol-3,4.

Because of the greater amounts of polyvalent metal oxides and hydroxides dispersible in the lubricating oil composition thereby, ethylene glycol is the preferred dihydric alcohol.

The amount of the dihydric alcohols used will depend in part upon the nature of the dihydric alcohol itself which is used, and as noted above, on the amount of polyvalent metal oxides and hydroxides which are to be dispersed. In general, the use of low molecular weight dihydric alcohols (e. g., ethylene glycol) results in obtaining a greater amount of the oxides and hydroxides dispersed in the lubricating oil than the use of a higher molecular weight dihydric alcohol (e. propylene glycol) when both are used in the same amounts by weight.

A sufiicient amount of dihydric alcohol is employed to disperse the polyvalent metal oxides or hydroxides in a reasonably short time. That is, the amount of dihydric alcohol used is sufiicient to cause substantial contact between the polyvalent metal oxides or hydroxides and the lubrieating oil composition in which the polyvalent metal oxides and hydroxides are to be dispersed. For this purpose, it is beneficial to use certain ratios by weight of the dihydric alcohol to the polyvalent metal oxide and hydroxide, which ratio may be from about 50 to 1 to about 2 to 1; 30 to 1 to about 10 to 1 being preferred.

The temperatures at which it is desired to promote the dispersion of the polyvalent metal oxides and hydroxides in the lubricating oil composition by means of the dihydric alcohol are dependent also to a large extent on the nature of the polyvalent metal oxides and hydroxides and the dihydric alcohols. It is preferred to use the minimum temperatures at which the dispersions will take place. In most instances it is not necessary to use temperatures above about 400 F. The dispersion will normally take place in a temperature range of 250 F. to 350 F., but, if it is necessary. temperatures as low as 200 F. may be used.

Once the polyvalent metal oxides and hydroxides have been dispersed in lubricating oils according to the present invention, the dispersions are stabilized by the addition of a dispersant which forms a part of the lubricating oil composition. When the dispersion of metal oxides and hydroxides has been thus stabilized, the dihydric alcohol is then removed from the composition by distillation or other means.

The dispersants which are used to stabilize the dispersions of polyvalent metal oxides and hydroxides prepared according to the present invention include polyvalent metal sulfonate, sulfates, phosphates, thiophosphates, phosphonates, thiophosphonates, phenates, naphthenates, carboxylates, etc.

Polyvalent metal sulfonate dispersants may be represented by the formulas (RSOsMM and [(R) aASOIilrIVI wherein R is a high molecular weight cyclic, straight-chained or branched-chained, saturated or unsaturated essentially hydrocarbon radical having a molecular weight ranging from about to about 800; A is an aromatic radical, such as benzene, naphthalene, anthracene, biphenyl, etc.; a is a number having a value of 1 to 4; M is a polyvalent metal, and a: is a number having a value equal to the valence of the polyvalent metal. As the metal, calcium, barium, strontium, mag nesium, zinc and lead are preferred.

By "essentially hydrocarbon (i. e., hydrocarbonaceous) radical is meant those radicals which are composed mainly of hydrogen and carbon, and include such radicals which contain, in addition, minor amounts of substituents such as chlorine, bromine, oxygen, hydroxyl groups, etc., which do not substantially affect their hydrocarbon character.

Examples of suitable hydrocarbonaceous radicals are the following: dodecane, hexadecane, eicosane, triacontane radicals; radicals derived from petroleum hydrocarbons such as white oil, wax, olefin polymers (e. g., polypropylene and polybutylene, etc.). The sulfonic acids used in preparing the sulfonates of this invention also include the oil-soluble sulfonic acids obtained from petroleum, such as the mahogany acids, and the synthetic sulfonic acids prepared by various methods of synthesis (e. g., sulfonic acids prepared by reacting a chlorinated white oil with benzene, using hydrofluoric acid as the catalyst, then treating the resulting white oil alkylated benzene with chlorosulfonic acid or fuming sulfuric acid to form a white oil benzene sulfonic acid).

The metal sulfonates are exemplified as follows: calcium white oil benzene sulfonate, magnesium white oil benzene sulfonate, calcium dipolypropene benzene sulfonate, magnesium dipolypropene benzene sulfonate, calcium mahogany petroleum sulfonate, magnesium mahogany petroleum sulfonate, calcium triacontyl sulfonate and magnesium triacontyl sulfonate, calcium lauryl sulfonate, magnesium lauryl sulfonate, etc.

Phosphonate dispersants which can be used according to this invention are represented by the empirical formula:

it R l|?0 o where R is a straight-chained or branchedchained, saturated or unsaturated substantially hydrocarbon radical having from '7 to 60 carbon atoms, and M represents a divalent metal, preferably calcium, barium, magnesium, lead and zinc.

The hydrocarbonaceous radicals can be derived from organic compounds, such as the following: cycloaliphatic hydrocarbons, such as methylcyclohexane, diethylcyclohexane, cetylcyclohexane, tetralin, ctc.; aliphatic hydrocarbons such as propane, propane, butane, butene, isobutane, pentane, pentene, isopentene, El-methylpentane, hexane, hexene, isohexane, isohexene, isoheptane, heptane, heptcne, octane, octene, iso-octane, cetane, hexadecane, octadecane, tetradecane, dodecane, hydrogenated olefin polymers; and aromatic hydrocarbons substituted by aliphatic or cycloaliphatic radicals such as toluene, xylene, hexylbenzene, cetylbenzene, octadecylbenzene, cyclohexylbenzene, etc.

Suitable radicals can also be obtained from mixtures of hydrocarbon, e. g, gasoline, kerosene, mineral lubricating oil fractions (e. g., white oil) and paraffin Wax.

The phosphonates used in this reaction can be preparedfromphosphonyl chlorides and phosphonic acids and their rsters, as set forth in the Jensen and Clayton patent application Serial No. 86,856, filed April 11, 1949.

Phosphate dispersants of this in ention are metal salts of substituted derivatives of acids of phosphorus, such as phosphorus acid, HaPOx: hypophosphoric acid, HzPOsI acid, H3PO'4; and pyrophosphoric acid, I'IdPilQ'l.

referably, the phosphates of this invention are metal salts formed from substituted oxyacids of pentavalent phosphorus of the following type formulas:

where R and R may be alkyl, aryl, alka-ryl, aralkyl, or cyclic non-benzenoid radicals. preferred to use substituted phosphoric acids containing at least 12 carbon atoms; especially preferred are alkyl or alkaryl substituted phosphoric acids having at least 12 carbon atoms in the molecule. Examples of the substituted acids of phosphorus which are used in the formation of the polyvalent metal salts are as follows:

Monoand di-lauryl phosphoric acids, mono and di-cetyl phosphoric acids, monoand dioctadecyl phosphoric acids, monoand di-cyclohexenyl phosphoric acids, monoand di-cetylphenyl phosphoric acids, etc.

The naphthenates contemplated herein as dispersants are the polyvalent metal salts of naphthenic acids; that is, the polyvalent metal salts of the carboxylic acids of the naphthenes, in particular, calcium, barium, zinc, lead, strontium, magnesium, manganese and copper salts of the petroleum naphthenic acids.

The phenates contemplated herein as dispersants are polyvalent metal salts of phenol and substituted phenols. Examples of polyvalent metal phenates include the calcium, barium, strontium, iron, lead, zinc, manganese, magnesium and copper salts of octyl phenol, decyl phenol, lauryl phenol, pentadecyl phenol, cetyl phenol, triacontyl phenol, etc.

The dispersants can be used in amounts of 0.1% to by weight of the total composition. However, because lubricating oil compositions orthopliosphoric It is x containing from 0.3% to 2.0% of the dispersants markedly increase the over-all rating of an engine, it is preferred to use these latter amounts.

The amounts of polyvalent oxides and hydroxides which can be stably dispersed in the lubricating oil depends on the effectiveness of the particular dispersant used. One part by weight of a dispersant can stably disperse as much as 0.2 part or more by weight of polyvalent metal oxides or hydroxides. For example, 1 part by weight of lead mahogany sulfonate can stably disperse 0.7 part by weight of lead oxide. Five parts by weight of calcium mahogany sulfonate can stably disperse 1 part by weight of calcium hydroxide. On a percentage basis, depending on the dispersant used and the polyvalent metal oxide and hydroxide dispersed, from 0.02% to 7% by weight of oxide and hydroxide can be. dispersed in the lubricating oil composition.

When the metal oxides and hydroxides have been dispersed in lubricating oil and the dis persion stabilized by a dispersant, the resulting lubricating oil composition is clear and filterable. The effectively stabilized colloidal dispersion is similar in appearance to a clear solution which can be filtered without removing any of the in gradients of the composition.

The polyvalent metal of the dispersant may be the same the polyvalent metal of the oxide or hydroxide dispersed; or the polyvalent metal of the dispersant may be different from the polyvalent metal oxide or hydroxide dispersed. For example, a calcium sulfonate may be used in a lubricating oil composition to stabilize a dispersion of lead oxide; or a calcium sulfonate may be used in a lubricating oil composition to stabilize a dispersion of lime.

Numerous variations of the methods presented here may be employed in preparing the dispersions of this invention. For example, the polyvalent metal oxides or hydroxides may be blended with the dispersants in the lubricating oil prior to being mixed with the dihydric alcohol, or the polyvalent metal oxides or hydroxides may be blended with the dihydric alcohol and the dispersant first before blending this mixture with the lubricating oil, or all of the ingredients may be blended together at once. It is preferred to mix the dihydric alcohols and the metal oxides or hydroxides first to obtain a colloidal dispersion or solution of the metal oxides or hydroxides in the polyhydric alcohols before mixing with the lubricating oil and dispersant.

As stated above, polyvalent metal oxides and hydroxides are stably dispersed in lubricating;- oil I compositions in accordance with this invention by heating a mixture of a dispersant, a polyvalent metal oxide and/or hydroxide, and a dihydric alcohol in a lubricating oil to a temperature of about 200 F. to 400 F. (250 F. to 350 F. being preferred) for a suflicient period of time until. the desired amount of polyvalent metal oxides and hydroxides are dispersed in the lubrieating oil composition.

The following examples are illustrative of the dispersions of polyvalent metal oxides and hy droxides stabilized by dispersants according to the present invention. (Examples I and II illustrate the preparation of the calcium sulfonates which were used to stabilize the colloidal dispersions of calcium oxide.)

30 parts by weight of a mineral oil having a viscosity of 350 at F. was added to 0 parts by weight of a sodium mahogany petroleum sulfonate having the following analyses:

Per cent Water 4.4 Oil 29.0 Sodium sulfonate 66.0 Inorganic salt 0.6

The combined weight of the sodium sulfonate was 515. The sodium sulfonate-mineral oil mixture was then added to 170 parts by weight of petroleum thinner having a boiling range of 186 F. to 290 F. This whole mixture was washed with dilute aqueous sodium chloride to remove the sodium sulfate. Calcium mahogany petroleum sulfonate was prepared by emulsifying 76 parts by weight of a 10% aqueous solution of calcium chloride in the mineral oil-sodium sulfonate blend. All inorganic salts were removed from the oil phase by water washes. The thinne and the water were removed by heating the mixture to a temperature of 320 F., at a pressure of 30 millimeters of mercury.

The mineral oil blend of neutral calcium mahogany petroleum sulfonate thus formed contained 1.75% calcium and 2.98% sulfurv Exam le II-Preparation of calcium dialkyl benzene sulfonate The dialkyl benzene used in this example was obtained by alkylation of benzene with polypropylene having a molecular weight of about 170, using hydrofluoric acid as the catalyst. The dialkyl benzene stock (37 parts by weight) was treated with 48 parts by weight of 27% fuming sulfuric acid, after which the acid and sludge settled out and was discarded. The sulfonated material was neutralized with aqueous caustic soda. To this stock, 29 parts by weight of a mineral oil having a viscosity of 350 SSU at 1 0 F. was added.

The mineral oil blend of crude sodium dialkyl benzene sulfonate was dissolved in 80 parts by weight of petroleum thinner having a boiling range of 186 to 290 R, which solution was then washed with aqueous sodium chloride to remove the sulfate present. The sodium dialkyl benzene sulfonate was converted to the calcium dialkyl benzene sulfonate by metathesis resulting from the addition of 50 parts by weight of 'a aqueous calcium chloride solution. The whole mixture was water washed to free the mixture of any residual inorganic salts. The thinner and the water were removed by heating the whole mixture to a temperature of 320 F. at a pressure of 30 millimeters of mercury.

The mineral oil blend of calcium dialkyl benzene sulfonate thus prepared contained 1.25% calcium and 2.25% sulfur.

The following Example III is representative of a preparation of a dispersion of calcium oxide in lubricating oil.

Example III-Stabilized colloidal dispersion of calcium oxide A mixture of 450 grams of a mineral oil solution of calcium mahogany petroleum sulfonate (the oil solution having 1.15% calcium), 6.? grams of calcium oxide and 320 grams of ethylene glycol were heated together with stirring at a temperature of 300 F. for a period of 3 hours. The ethylene lycol was then removed by heating to a temperature of 320 F. at a pressure of 3 millimeters of mercury. The remaining mineral oil mixture was filtered. This filtered mineral oil solution contained 2.14% calcium, which showed the presence of 86% more calcium in the lubricating oil after the dispersion than before.

Further preparations of stable dispersions of polyvalent metal oxides and hydroxides are well illustrated by the data presented in the table, which presents the reaction conditions and the analytical results of the final lubricating oil composition. Calcium mahogany petroleum sulfonate was the dispersing agent (the detergent) used. Column 3 of the table gives the amount of calcium in the lubricating oil solution prior to the dispersion, and column 8 gives the amount of calcium present in the lubricating oil solution after the dispersion and filtration. The dispersions were prepared by heating mineral oil solutions of calcium mahogany petroleum sulfonate and calcium oxide in the presence of ethylene glycol at a temperature ranging from 290 to 300 for periods ranging from 3 to 11 hours. The mineral oil solutions of calcium mahogany petroleum sulfonates were prepared according to the method illustrated by Example I.

In all the examples of the table, ethylene glycol was used as the dihydric alcohol.

TABLE Sull'onnlc Concentrate I I Grams Grams Reaction 53; Per- No. CaO Solvent Temp, cont Amount Per- Used Uscd F. E Ga Used com (Grams) On M i g r sec 1.31 l l5 400 1mm .1 2 700 D. 20 40(1 300 8 Z 800 ll. 55 21 400 300 It 300 l. 17 6. 5 290 4- 300 1.17 6. 5 60 290 l 300 l. 17 6. 5 30 290 4- 300 l. 17 6. 5 15 290 l 4 500 1.15 12.5 0 son :0 l l l 1 Example IV-Coll0idal dispersions of calcium oxide in lubricating oil stabilized by calc um naphthenate A mixture of 370 grams of a mineral oil solution of calcium naphthenate (the oil solution having 2.57% calcium) and grams of calcium oxide in ethylene glycol (the ethylene glycol solution contained 3.6% calcium) was heated to 380 F. for a period of 2 hours. Due to the increase in the viscosity an additional 100 grams of a mineral oil were added, and the mixture was heated for an additional period of 1 hour. The ethylene glycol was then removed by heating to a temperature of 450 F. at atmospheric pressure. The dispersion thus prepared contained 2.89% calcium, of which 2.02% was accounted for by the calcium in calcium naphthenate.

As noted hereinabove, polyvalent metal oxides and hydroxides which are dispersible according to above procedures are useful as additives in lubricating oils for increasing the over-all rating of the engine. As shown by a modified L-l Caterpillar Engine Test, these dispersions of polyvalent metal oxides and hydroxides assist in keeping piston skirts clean, preventing deposit formation in ring grooves and in ring belt areas,

and also decreasing corrosion. This L-l Caterpillar Test was run for a period of 120 hours in a single cylinder Caterpillar engine having an exhaust temperature of 800 F., using a fuel containing 0.1% sulfur.

Caterpillar Engine Tests (L-l) were made with a lubricating oil composition containing sulfurized diparaffin sulfide, sulfurized calcium cetyl phenate, zinc cetyl phenyl dithiophosphate, and a calcium mahogany petroleum sulfonate which contributed 0.028% total calcium to the oil (none of which was dispersed calcium). The top ring groove deposit number was 42 (a rating of 0" indicates a clean groove, and a rating of "100 indicates a groove filled with gum deposits). After testing the same lubricating oil composition in which calcium oxide was dispersed in the lubricating oil by calcium mahogany petroleum sulfonate (0.013% being dispersed calcium present), the top ring groove deposit number was 23. Thus, the stabilized dispersion of calcium oxide resulted in approximately 45% reduction of top ring groove deposit (from 42 to 23) over that of the calcium mahogany petroleum sulfonate alone.

In addition to the components of this invention, other groups of additives may be used in the lubricating oil compositions. The lubricating oil compositions may contain oxidation inhibitors, such as organo esters of phosphorus (e. g., zinc cetylphenyl dithiophosphate and calcium cetylphenyl dithiophosphate); metal salts of thiocarbamie acids (e. g., zinc dibutyl dithiocarbamate) sulfides (e. g., sulfurized diparaffin sulfide sulfurized olefins, Pass-1311718118 reaction products, eta); amines (phenyl alpha naphthyl amine; i,4-diamino (dodecyl) anthraquinone; p,p-dioctyl dip henyl amine; N-diethyl thiocarbamyl-p phenylene diarnine, etc).

Furthermore, the lubricating oil composition may contain pour point depressants, corrosion inhibitors, oiliness agents, extreme pressure agents, blooming agents, compounds for enhancing the viscosity index of hydrocarbon oils; grease-forming agents, other dispersants, etc.

We claim:

1. A process of incorporating polyvalent metal base substances in lubricating oils to produce stable, filterable compositions, which comprises the steps of forming a mixture of a lubricating oil,

a dihydric alcohol of less than 6 carbon atoms, .1

an oil soluble polyvalent metal dispersant, and an inorganic polyvalent metal base selected from the group consisting of oxides and hydroxides, said dihydric alcohol being present in the mixture in an amount ranging from 2 to 50 moles for each mole of said inorganic metal base, and heating said mixture for a sufficient time to effect the dispersion of said inorganic metal base in the lubricating oil-dispersant composition and to remove dihydric alcohol.

2. The process of claim 1 wherein said mixture is formed in stages by first mixing said dihydric alcohol with said metal base and then blending said resulting mixture with said lubricating oil and stabilizing dispersant.

3. In the process of incorporating polyvalent metal substances in lubricating oils to produce stable, filterable compositions, which comprises the steps of forming a mixture of an inorganic polyvalent metal base selected from the group consisting of oxides and hydroxides, 2 to 50 moles of ethylene glycol per mole of said inorganic base, a polyvalent metal dispersant in an amount of at least 1 part by weight for each 0.? part of said inorganic metal base, and lubricating oil sufficient to give an inorganic metal base concentration in said lubricating oil of 0.02 to 7% by weight, and heating said mixture for a sufficient time to disperse said inorganic metal base in said lubricating oil and to remove a substantial portion of said ethylene glycol.

4. Process of claim 3 wherein said metal base is an alkaline earth metal base.

5. Process of claim 3 wherein said dispersant is a polyvalent metal sulfonate.

6. A process for incorporating polyvalent metal base substances in lubricating oils to produce stable, filterable compositions, which comprises the steps of first mixing an inorganic alkaline earth metal base selected from the group consisting of oxides and hydroxides with 10 to 30 moles of ethylene glycol per mole of said metal phase, dispersing said mixture of metal base and ethylene glycol in a lubricating oil containing an alkaline earth metal sulfonate dispersant, said dispersant being present in an amount of at least 1 part by Weight for each 0.? part of said inorganic metal base, and said lubricating oil being present in an amount sufficient to give an inorganic metal base concentration in said lubricating oil of 0.02 to 7% by weight, and heating the resulting dispersion for a sufficient time to remove a substantial proportion of said ethylene glycol.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 2,043,638 Watts June 9, 1936 2,079,051 Sullivan et al May 4, 1937 2,285,453 Merkle June 9, 1942 2,470,913 Bjorksten et a1 May 24, 1949 2,485,861 Campbell Oct. 25, 1949 

1. A PROCESS OF INCORPORATING POLYVALENT METAL BASE SUBSTANCES IN LUBRICATING OILS TO PRODUCE STABLE, FILTERABLE COMPOSITIONS, WHICH COMPRISES THE STEPS OF FORMING A MIXTURE OF A LUBRICATING OIL, A DIHYDRIC ALCOHOL OF LESS THAN 6 CARBON ATOMS, AN OIL SOLUBLE POLYVALENT METAL DISPERSANT, AND AN INORGANIC POLYVALENT METAL BASE SELECTED FROM THE GROUP CONSISTING OF OXIDES AND HYDROXIDES, SAID DIHYDRIC ALCOHOL BEING PRESENT IN THE MIXTURE IN AN AMOUNT RANGING FROM 2 TO 50 MOLES FOR EACH MOLE OF SAID INORGANIC METAL BASE, AND HEATING SAID MIXTURE FOR A SUFFICIENT TIME TO EFFECT THE DISPERSION OF SAID INORGANIC METAL BASE IN THE LUBRICATING OIL-DISPERSANT COMPOSITION AND TO REMOVE DIHYDRIC ALCOHOL. 